1. Field of the Invention
This invention relates to aircraft brake testers. More particularly, this invention relates to apparatus for testing a plurality of brake cylinders on a plurality of aircraft disc brakes.
2. Description of the Related Art
Aircraft are equipped with a plurality of disc brakes, each having a brake shoe on each side of a brake disc. During the braking operation, a set of cylinders for each brake, one for each shoe, presses the shoes against the brake disc to frictionally stop the rotation of the brake disc. The cylinders are hydraulically actuated, with each brake being hydraulically actuated independently of the remaining brakes and each cylinder within each brake being hydraulically actuated independently of the remaining cylinders.
Occasionally, due to, for example, a leak in the hydraulic system or a malfunctioning brake valve, the hydraulic system will not uniformly apply pressure to each of the cylinders. In this event, one brake of the plurality of brakes may not stop the rotation of the respective brake disc at the same rate as another brake would stop the rotation of its respective brake disc. Still further, one cylinder of a particular brake may not press against its respective brake shoe with the same force as the oppositely disposed cylinder of the same brake. In either case, the pilot may be unable to smoothly and safely bring the aircraft to a stop if the cylinders of each respective brake are not uniformly pressing the brake shoes or if the brakes of one wheel of the airplane are not stopping at a uniform rate as brakes of another wheel of the airplane.
Methods and apparatus for testing the pressure level in a hydraulic line are known. A method and apparatus, however, is needed to simultaneously detect the pressure levels in the hydraulic lines applied to each of the cylinders for a plurality of disc brakes and to calculate subtle differences between the instantaneous pressure levels to diagnose brake defects before the potential occurrence of significant brake failure.